Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 766 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.781 − 349 =
2. 2.244 − 159 =
3. 3.661 − 207 =
4. 4.657 − 149 =
5. 5.586 − 287 =
6. 6.896 − 297 =
7. 7.501 − 338 =
8. 8.775 − 169 =
9. 9.761 − 199 =
10. 10.925 − 558 =
11. 11.285 − 268 =
12. 12.624 − 357 =
13. 13.850 − 797 =
14. 14.747 − 599 =
15. 15.877 − 359 =
16. 16.909 − 799 =
17. 17.995 − 197 =
18. 18.947 − 629 =
19. 19.666 − 598 =
20. 20.895 − 697 =
21. 21.428 − 339 =
22. 22.900 − 799 =
23. 23.859 − 367 =
24. 24.616 − 197 =
25. 25.898 − 798 =
26. 26.928 − 497 =
27. 27.705 − 397 =
28. 28.519 − 498 =
29. 29.991 − 458 =
30. 30.715 − 498 =
31. 31.530 − 299 =
32. 32.839 − 379 =
33. 33.942 − 699 =
34. 34.924 − 598 =
35. 35.885 − 338 =
36. 36.656 − 598 =
37. 37.606 − 399 =
38. 38.795 − 199 =
39. 39.714 − 398 =
40. 40.790 − 249 =

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